a human limb; technically the part of the superior limb between the shoulder and the elbow but commonly used to refer to the whole superior limb. arm, branch, limb (noun). any projection that is thought to resemble a human arm.
Vertebrates are the most organized organisms on Earth. They belong to the sub-phylum Vertebrata. They are not the most numerous group of animals, they are the most advanced group of animals.The characteristics that makes vertebrates special are the presence of the spinal cords, vertebrae and notochords.hey belong to the Phylum Chordata. The characteristics of phylum chordata is the presence of notochord, a dorsal hollow nerve cord and paired pharyngeal gill slits. The members of subphylum Vertebrata possess notochord during the embryonic period.
Animals can be classified into two main groups: vertebrates and invertebrates. The main difference between vertebrates and invertebrates is that invertebrates, like insects and flatworms, do not have a backbone or a spinal column. Examples of vertebrates include humans, birds, and snakes.